Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Emptying of Nitric Acid storage tank(98% HNO3)

Emptying of Nitric Acid storage tank(98% HNO3)

Emptying of Nitric Acid storage tank(98% HNO3)

I'm working at Fire and Safety division of Huchems fine chemical corporation in Rep' of Korea.
The company's website is http://www.huchems.com
Huchems corp. is the Korea's largest producer of Concentrated Nitric Acid(CNA: 98%) with a capacity of 104,300 MTPA.
We have two CNA plants designed by CHEMICO(33,000MTPA) and PLINKE(71,300MTPA).
The plants were built in 1979 and 1990. We have two CNA storage tanks made of aluminum.
The capacity of the thanks are 1,360 and 1,019KL each.
As our production quantity is little short of demand, we have to buy some CNA from the other domestic companies.
We use the CNA to produce DNT(Di-nitro-toluene).

The Korean law, revised in 1999, states that the storage tanks for dangerous chemicals of over 1,000 KL capacity must be inspected internally every 10 years.
There has been no need for the internal inspection of the CNA storage tanks according to the previous law.
So, there has been no internal inspection for the CNA storage tanks.

For over 25 years, nobody performed the internal inspection of the CNA tanks in the company.
Besides the danger relating the task, it will cost too much for us to treat the acidic waste from the CNA tanks.
I heard that if we try to clean aluminium tank with water, it will form weak nitric acid inside the tank and will corrode the tank very fast, since Aluminium tank is not suitable for Nitric Acid less than 90% concentration.

In this regard, I would appreciate it if someone could provide me any idea for this matter.

Many thanks in advance,

Jae-Hyuk Im

* You can see picture of the CNA storage tanks at the following web page.

* If someone has proprietary technical reference, please contact me personally.  We are willing to pay for the information on the required works for the inspection. (Detailed procedure for emptying, cleaning, waste water disposal, safety)

RE: Emptying of Nitric Acid storage tank(98% HNO3)

You should post this question in the Corrosion engineering forum.  You should get more responses there.

RE: Emptying of Nitric Acid storage tank(98% HNO3)

Does the law tell you how to inspect the tank interior, or what to inspect for?  Does a person have to enter the tank or can you use a video borescope (some have very long articulated probes).  After you empty the tank, can you establish a dry air purge (to prevent moist air entry) and perform borescope inspections?

RE: Emptying of Nitric Acid storage tank(98% HNO3)

Thank you very much for your consideration.
1) The welding seams of the bottom plate must be inspected using non-destructive test.(15% of all welding seams)
2) The thickness of the bottom plate must be checked.
3) Inspectors must enter the tank for vaccum box test.
4) The problem is that "emptying" and "dry purging" the tank is very very difficult task for me.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close